Year	gross (GPI)
1970	0.807900011539459
1971	0.805980026721954
1972	0.802209973335266
1973	0.798749983310699
1974	0.795620024204254
1975	0.856869995594025
1976	0.888890027999878
1977	0.896250009536743
1978	0.894729971885681
1979	0.888870000839233
1980	0.891550004482269
1981	0.888450026512146
1982	0.879480004310608
1983	0.874949991703033
1984	0.879700005054474
1985	0.882730007171631
1986	0.905969977378845
1987	0.91237998008728
1988	0.919969975948334
1989	0.925559997558594
1990	0.933520019054413
1991	0.938210010528564
1992	0.94556999206543
1993	0.947269976139069
1994	0.951059997081757
1995	0.957899987697601
1996	0.963010013103485
1997	0.967180013656616
1998	0.970640003681183
1999	0.974279999732971
2000	0.975120007991791
2001	0.980019986629486
2002	0.981280028820038
2003	0.983399987220764
2004	0.986540019512177
2005	0.98387998342514
2006	0.9826700091362
2007	0.981289982795715
2008	0.978429973125458
2009	0.979709982872009
2010	0.976440012454987
2011	0.977540016174316
2012	0.980929970741272
2013	0.986000001430511
2014	0.989340007305145
2015	0.987879991531372
2016	0.992399990558624
2017	0.994570016860962
2018	0.995369970798492
2019	0.995369970798492
2020	0.992680013179779